A known autostereoscopic display device is illustrated in FIG. 1. This known device 1 comprises a two dimensional liquid crystal display panel (LCD) 3 having a row and column array of display pixels 5 acting as a spatial light modulator to produce the display in the form of a static image or dynamic images such as, for example, video. For the sake of clarity, only a small number of display pixels 5 are shown in FIG. 1. In practice, the display panel 3 might, for example, comprise about one thousand rows and several thousand columns of display pixels 5.
The structure of the liquid crystal display panel 3 is entirely conventional. In particular, it comprises a pair of spaced transparent glass substrates, between which an aligned twisted nematic or other liquid crystal material is provided. The substrates carry patterns of transparent indium tin oxide (ITO) electrodes on their facing surfaces. Polarizing layers are also provided on the outer surfaces of the substrates.
Each display pixel 5 is associated with a switching element, such as a thin film transistor (TFT) or thin film diode (TFD). The display pixels are operated to produce the display by providing addressing signals to the switching elements, and suitable addressing schemes will be known to those skilled in the art.
The display panel 3 is illuminated by a light source 7 comprising, in this case, a planar backlight extending over the area of the display pixel array. Light from the light source 7 is directed through the display panel 3, with the individual display pixels 5 being driven to modulate the light and produce the display.
The display device 1 also comprises a lens arrangement in the form of a lenticular sheet 9, arranged over the display side of the display panel 3, which performs a view-forming function. The lenticular sheet 9 comprises an array of semi-cylindrical lenticular lens elements 11. Each lenticular lens element 11 has a longitudinal axis 10 and the lens elements are extending such that their respective longitudinal axes are oriented parallel to one another. Only one lenticular lens element 11 is shown in FIG. 1 with exaggerated dimensions for the sake of clarity. Thus, an array of elongate lenticular lens elements 11 extending parallel to one another overlies the display pixel array, and the display pixels 5 are observed by a user or viewer through these lenticular lens elements 11. The lenticular lens elements 11 act as a light output directing means to provide different images, or views, from the display panel 3 to the eyes of a user positioned in front of the display device 1.
The above described device provides an effective autostereoscopic, or three dimensional, display device if the produced display or image comprises multiple views. Such a display or image will, hereinafter, be indicated to be an autostereoscopic image having at least two sub-images, each one of them representing a different view of the object to be displayed by the image. The at least two views are then displayed by the lens arrangement so that a viewer perceives a stereo, 3D or look-around impression of the object. In an arrangement in which, for example, each lenticular lens element 11 is associated with two columns of display pixels 5, the display pixels 5 in each column provide a vertical slice of a respective two dimensional sub-image. The lenticular sheet 9 directs these two slices and corresponding slices from the display pixel columns associated with the other lenticular lens elements 11, to the left and right eyes of a user positioned in front of the sheet, so that the user observes a single stereoscopic image.
In modifications of such a device, the lenticular lens elements may be oriented with their longitudinal axes slanted with a slant angle with respect to the pixel column direction of the display panel or autostereoscopic image. The modification provides advantages in terms of pixel resolution loss sharing between horizontal and vertical display panel directions. As this is not the subject of the present invention, for a more detailed explanation on the effects and mode of application reference is made to U.S. Pat. No. 6,064,424.